Chemical Engineering Seminar

Spraying the way to shape- and architecturally-controlled nanostructures

Sara Skrabalak, Assistant Professor, Chemistry, Indiana University

The physicochemical properties of nanocrystals are determined by a set of structural parameters that include their size, shape, composition and architecture. Yet despite their promise to many applications, it remains a grand challenge to prepare structurally well-defined nanomaterials via scalable routes. Ultrasonic spray pyrolysis - an aerosol means of materials synthesis - has the potential to address this need on account of its continuous nature, with each aerosol droplet serving as a micon-sized reactor. However, polycrystalline microspheres are typically produced. This trend arises because each droplet has multiple nucleation sites and the selected chemical routes provide no means of inhibiting agglomeration of the individual crystallites which form. Yet, it will be shown that discrete and single-crystalline, shape-controlled nanocrystals can be achieved by integrating new chemical methods with spray pyrolysis. Examples include the integration of solid state metathesis reactions and molten salt syntheses, which were used to prepare visible light photocatalysts. These methods were expanded to facilitate the continuous generation of porous microspheres via aerosol-assisted self assembly, with utility in affinity chromatography applications.